A conventional particle beam system includes a particle beam source for generating a particle beam, and a high voltage source for providing an acceleration voltage, in order to accelerate the charged particles of the particle beam that are generated by the particle beam source to a desired kinetic energy. The conventional system further comprises a pair of deflection plates, between which a beam path of the particle beam extends. The first deflection plate of the pair can be connected to a high voltage source, and the second deflection plate of the pair can be selectively connected, via a switch, to this high voltage source or to another voltage source providing an electric potential different from that of the high voltage source. If this second deflection plate is connected to the high voltage source, the particle beam is substantially not affected when traversing the pair of deflection plates and propagates essentially along a straight line. If the second deflection plate is connected to the other voltage source however, an electric field is produced between the two deflection plates. Such electric field deflects the particle beam, so that it is, for example, incident on a plate downstream of the deflection plates and is absorbed by such plate. Depending on a switching state of the switch, the particle beam is selectively available downstream of the plate and can therefore be switched on and off by operating the switch.
It has been found that immediately after the beam has been switched on, the conventional particle beam system does not provide desired operating characteristics and that the desired operating characteristics are achieved only after a fairly long period of time.